1. Field of the Invention
This invention relates, in general, to apparatus for controlling light and heat transference, and, in particular, to slat assemblages for controlling light and heat to greenhouses.
2. Description of the Prior Art
The prior art, as typified by the plantbed cover assemblies of N. E. Rowell, U.S. Pat. No. 3,874,114; W. H. Garbade, U.S. Pat. No. 2,857,634; and H. Badertscher, U.S. Pat. No. 4,128,307, includes several devices for controlling the amount of heat and light entering a greenhouse. The Rowell patent illustrates a hinged frame mountable over a plantbed and provided with moveable vanes. To gain access to the plants the framework is simply lifted off a supporting framework. The vanes of the Rowell invention provide shade and also control the amount of moisture entering the plantbed. Use for such devices on conventional greenhouses is prohibited by the size and weight of any such unit.
The Badertscher patent illustrates a lightweight device which is effective for controlling the incidence of heat and light radiation in greenhouses. That invention discloses a plurality of slats lying in a horizontal plane and serving as a light reflective ceiling within a greenhouse. The slats of the Badertscher invention consist of thin reflective aluminum foil which are not self-supporting and which provide only thermal reflective insulation. While providing a significant advance over the prior art, the Badertscher invention does not provide a ceiling of low thermal conductivity and therefore is ineffective in preventing such heat loss. Aluminum foil has a high thermal conductivity, permitting significant heat loss through conduction. Furthermore, the Badertscher invention does not prevent the unwanted dripping of moisture due to condensation.